ONLY works on analog phones, not electronic system or VoIP phones.
It simply turns off the phone line, so you can't make or receive calls, and incoming callers hear a busy signal.
Great for turning off a second or third line that hunts from the first line so you can use one answering machine, or turning off the phone line when you don't want to be disturbed.
If you want to make the line busy automatically on a certain schedule, use our Automatic Make Busy Switch (#KIT7L) with an AC Outlet Timer or Smart Outlet.